Katsutoshi Sato,^1,2 Takashi Imai,² Ryuichi Okayasu,³ Takashi Shimokawa<sup>1,*

1</sup>a Cancer Metastasis Research Team
²b Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy
³c International Open Laboratory, National Institute of Radiological Sciences, Chiba, Japan

^*Address for correspondence: Cancer Metastasis Research Team, Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba, 263-8555, Japan; e-mail: takshi@nirs.go.jp.